“Barging in on Kim’s booty selfie,” Kendall captioned her Instagram picture, which showed both sisters showing off their assets in sports bras and tight, black workout pants while at the gym (Kim’s face is obscured by her phone).

“It sucks when people make up surgery or photoshop lies when I am so disciplined & work so hard!” she wrote. “Just trying to motivate others & show anyone struggling with weight they can totally achieve whatever they want if they are dedicated!”